Imported from sickn33/agentic-awesome-skills (
skills/gh-attach/SKILL.md). Install upstream withnpx skills add sickn33/agentic-awesome-skills --skill gh-attach. Copyright stays with the author (MIT).
Upload and download GitHub user-attachments (gh-attach)
GitHub has no public API for user-attachments. The web UI uses an internal
endpoint that mints github.com/user-attachments URLs whose visibility follows the
repository they belong to. gh-attach
(MIT, sudosubin) replicates that drag-and-drop flow as a gh CLI extension, so an
agent can upload a local file from the terminal, get a URL back, and later download
an attachment URL to a file.
Overview
This skill drives gh-attach to turn a local file (screenshot, image, PDF, zip,
log, or video) into a hosted GitHub user-attachments URL, then embeds that URL
into a pull request, issue, or comment. It also downloads an existing attachment
URL back to a local file. GitHub auto-renders the URL as an image, video, or file
wherever it is pasted, and the URL inherits the repository's visibility, so a
private-repo upload stays private. It works against GitHub Cloud and GitHub
Enterprise Server.
When to Use This Skill
Use this skill when asked to:
- "Attach a screenshot to the PR" or "add an image to the PR description"
- "Attach this file (PDF, zip, log, video) to the issue or comment"
- "Embed before/after screenshots" in a PR, issue, or README
- "Download this GitHub attachment" from a
user-attachmentsURL
How It Works
Step 1: Verify prerequisites
gh auth status # gh installed and authenticated
gh extension install sudosubin/gh-attach --pin v0.4.2 --force
gh extension list | grep -F 'sudosubin/gh-attach' # require the reviewed v0.4.2 release
Uploads use a GitHub user_session browser cookie, not the gh token (that
endpoint rejects tokens). By default gh must be authenticated so gh-attach can
select the matching browser account (Chromium family, Firefox family, or Safari).
If the wrong account is selected, add --browser <name> --profile <name>. Obtain
explicit approval before allowing the pinned extension to access that interactive
browser profile. Headless and CI uploads are intentionally unsupported: never export,
store, or pass a raw user_session cookie to the extension.
Step 2: Upload
# Use an absolute quoted path; -R is optional inside a repo working dir.
URL=$(gh attach "/abs/path/screenshot.png" -R <owner>/<repo>)
gh attach prints the URL on one line to stdout. For GitHub Enterprise Server,
use -R host/owner/repo. Capture the output; it is the embeddable reference.
Step 3: Embed into the PR / issue / comment
printf '## Screenshots\n\n%s\n' "$URL" \
| gh pr comment <pr> -R <owner>/<repo> --body-file -
Use gh pr edit, gh issue comment, or gh issue edit with --body-file - for
other targets. Always pass --body-file - (not inline --body) so multi-line
bodies and special characters cannot break shell quoting. GitHub auto-renders the
URL, so paste it as-is.
Step 4: Download
# Specify the destination explicitly.
gh attach download "$URL" -O "/abs/path/out.png"
Downloads of private attachments use the active gh token, with browser cookies as
an authorization fallback.
Examples
- Attach a screenshot to PR #42: upload the file, then append the URL under a
## Screenshotsheading in the PR body withgh pr edit ... --body-file -. - Embed before/after screenshots in a README: upload both files, paste the two URLs into the README at the relevant section.
- Download an attachment for review: run
gh attach download "$URL" -O out.zipto fetch auser-attachmentsfile locally.
Best Practices
- Resolve globs to absolute paths first, and quote paths that contain spaces or Unicode.
- For display sizing, embed an HTML tag instead of the bare URL:
<img width="800" src="$URL">. - Keep uploads interactive. Do not place a GitHub browser session in CI, an environment variable, a secret store consumed by this extension, or an agent log.
gh-attachcan upload multiple files concurrently and emit Markdown or JSON output with jq-style filtering when you need to script around the result.
Limitations
- Interactive session cookie required. A
user_sessioncookie grants full account access and is not scoped like a PAT. The supported path is the reviewed, pinned extension reading an explicitly approved local browser profile; CI and headless cookie injection are out of scope. - Write access to the target repo is required to upload.
- Private-repo attachments stay private: the
user-attachmentsURL inherits repo visibility, so an anonymous fetch on a private repo returns 404 or 403 by design. - GitHub Cloud and GitHub Enterprise Server each decide which file extensions and content types they accept.
- The skill embeds the URL itself;
gh attachonly prints it.
Security & Safety Notes
- The
user_sessioncookie is a full-account credential. Never print, export, paste, log, or commit it, and never make it available to CI or headless agents. - Do not install or upgrade
gh-attachfrom a moving branch or an unpinned latest release. Re-review and update the exact--pinonly in a repository change. - Uploaded attachments are auto-rendered by GitHub, so only upload files you intend to share with everyone who can view the target repository.
- Confirm the destination
-R <owner>/<repo>before uploading so an attachment is not created against the wrong repository.